(Adds details on evacuations and locations of fire)
By Keith Coffman
COLORADO SPRINGS, Colo., June 12 (Reuters) - A wind-whipped Colorado wildfire menaced the state's second-largest city on Wednesday, forcing thousands of residents to flee flames and choking smoke and ruining between 80 and 100 homes in a wooded subdivision since it erupted a day earlier.
The fast-moving blaze was raging uncontrolled about 15 miles (24 km) northeast of Colorado Springs, and could soon threaten more homes if winds increase as expected later on Wednesday afternoon, El Paso County Sheriff Terry Maketa told reporters.
The blaze, which erupted on Tuesday and quickly ripped through Colorado's Black Forest, comes as firefighters in the U.S. West worry that entrenched drought conditions could lead to a more intense fire season, particularly in California.
"It's a very hot, very active, difficult fire" said Dave Rose, spokesman for El Paso County, where the so-called Black Forest Fire was burning about 30 miles (48 km) away from where another massive blaze destroyed hundreds of homes on the outskirts of Colorado Springs less than a year ago.
"Unfortunately, the wind's starting to pick back up again, and so the wind will blow the fire back into areas that are still rich with fuel" in the form of trees, Rose said.
Another fire in a neighboring county on Tuesday forced the closure of one of the state's top tourist attractions and the evacuation overnight of more than 900 inmates from a prison.
Maketa said the Black Forest blaze quickly reached a residential community near Colorado Springs, where it destroyed between 80 and 100 homes and an unknown number of outbuildings.
Evacuation notices went out to 2,600 homes housing 7,300 people, and Army National Guard troops have been deployed to help police prevent looting. The smell of smoke hung in the air in areas 30 miles (48 km) away from the blaze.
Maketa compared the fire to Colorado's most destructive wildfire, the so-called Waldo Canyon Fire, which killed two local residents and reduced about 350 homes to ashes last June. More than 30,000 people in the area had been under mandatory evacuation orders during that fire.
Firefighters have been unable to create any containment lines around the Black Forest fire, which Maketa said was estimated to cover an area of 7,500 to 8,000 acres (3,035 to 3,240 hectares). No injuries have been reported.
The blaze was especially intense at its northern flank, where trees were engulfed in a wall of flames that flared from ground-level to the tops of the canopies. A large air tanker could be seen making passes over the blaze dropping payloads of fire-retardant.
Colorado Springs is located between the foothills of the Rocky Mountains on the west and the edge of the Great Plains on the east. The other Colorado fire, 50 miles (80 km) to the southwest in neighboring Fremont County, also broke out on Tuesday and quickly spread to 3,800 acres (1,540 hectares).
That blaze prompted the evacuation of the Royal Gorge Bridge & Park, whose span is billed as the world's highest suspension bridge, the U.S. Bureau of Land Management said in a statement.
The bridge, which was not directly threatened by flames, stretches nearly 1,000 feet (300 meters) above the Arkansas River for a quarter-mile and is one of Colorado's most visible tourist destinations. Fire managers said the river was closed to rafting.
The fire near the river prompted the evacuation of 905 prisoners overnight from the Colorado Territorial Correctional Facility in Canon City to other prisons as a precautionary measure, said state corrections spokeswoman Alison Morgan.
She said the fire had not reached the prison, which houses many inmates with mental health and other medical needs including wheelchairs.
The fires came as the U.S. Drought Monitor says that nearly 16 percent of Colorado suffers from "exceptional" drought conditions - the most severe rating possible - while over 26 percent of the state is in the "extreme" category.
The National Weather Service said single-digit humidity values and temperatures in the upper 90s Fahrenheit (upper 30s Celsius), combined with wind gusts in excess of 40 miles (65 km) an hour have created "very high to extreme fire danger" in Colorado for most of the week.
Investigators were seeking the cause of both fires. (Additional reporting by Colleen Jenkins and Laura Zuckerman; Writing by Alex Dobuzinskis; Editing by James Dalgleish, Cynthia Johnston and Carol Bishopric)